I know it's frustrating!
One thought is that the steroid (prednisolone?) you're giving Victor may be the culprit. Steroids raise BG numbers. The other culprit is what you're feeding your cat. Unless you've already transitioned to a low carb diet and not updated your signature, the dry food you're giving Victor is outrageously high in carbohydrates. Some of the ingredients are corn, brewers rice, corn gluten meal, brown rice, wheat gluten, pea fiber, powdered cellulose, dried plain beet pulp -- all of these are carbs and your cat isn't really able to process them. (My favorite is the powdered cellulose -- aka saw dust). The dental diet is approximately 44% carb. We recommend a low carb diet that's under 10% carb and most people use food that's about 5% or less. Cats are obligate carnivores and can't metabolize carbs.
One observation... Please always get a before bed test. I know it may seem like numbers are always high so why bother until you see more movement. However, many cats do experience lower numbers at night. You have no way of knowing if there's a negligible drop or if Victor is dropping into yellows at night and bouncing into a black at AMPS.
You've been at the current dose for 14 cycles so you're fine to increase. If you change his diet, do not increase the dose since a low carb diet can dramatically drop the numbers.
Are you testing for ketones? If not, given that your kitty is prone to ear infections, I would suggest testing as a precaution.You can find Ketostix at any pharmacy. You dip the strip into your cat's urine.
